I preordered Star Citizen back in 2012 or 2013. Whenever the original Kickstarter was. I've kind of forgotten about it. I've never preordered another game--or anything really. And I don't think this was a bad experience.
I haven't received a game yet, but I have played some demos that were really fun. I've seen hours of content (Sure, that content is freely available, but so is NPR), read some great stories, and had some great conversations about the game.
In 2013 I paid $60 for a game I have not yet played. That year I also went to a casino one night with $80 in my pocket. Both times I came away with nothing but a fun experience and some stories. In both cases I feel like I paid for some entertainment and received it.
This isn't a post to excuse vaporware titles on Steam Greenlight or preordering broken-on-launch games. Quite the contrary. I won't buy EA games until at least a year after they come out. I will NEVER buy a pre-release game on Steam. But I bought Star Citizen. I took a gamble, and I had some fun. I wouldn't have done that if I didn't think there would be some fun along the way.
Star Citizen could never come out, and I wouldn't really feel cheated, because I still got something out of it.